Bladed solar thermal receivers for concentrating solar power

ABSTRACT

A bladed solar thermal receiver for absorbing concentrated sunlight is disclosed. The receiver includes a plurality of panels arranged in a bladed configuration for absorbing sunlight. The bladed configurations can be radial or planar. The receiver design increases the effective solar absorptance and efficiency by providing a light trap for the incident solar radiation while reducing heat losses from radiation and convection.

RELATED APPLICATION

This application is a Divisional of U.S. patent application Ser. No.14/535,100, filed of Nov. 6, 2014, entitled “BLADED SOLAR THERMALRECEIVERS FOR CONCENTRATING SOLAR POWER,” which claims priority to U.S.Provisional Patent Application No. 61/901,628, filed on Nov. 8, 2013,entitled “SOLAR THERMAL ADVANCED RECEIVER FOR CONCENTRATING SOLAR POWERTOWERS,” the entireties of which are incorporated herein by reference intheir entireties.

STATEMENT OF GOVERNMENT INTEREST

The United States Government has rights in this invention pursuant toContract No. DE-AC04-94AL85000 between the United States Department ofEnergy and Sandia Corporation and Contract No. DE-NA0003525 between theUnited State Department of Energy and National Technology & EngineeringSolutions of Sandia, LLC, both for the operation of the Sandia NationalLaboratories.

FIELD

The present disclosure is generally directed to solar thermal receivers,and more particularly to solar thermal receivers having structures andgeometries that increase effective solar absorptance and efficiency.

BACKGROUND

Mounting concerns over the effect of greenhouse gases on global climatehave stimulated research focused on limiting greenhouse gas emissions.Solar power generation is particularly appealing because substantiallyno greenhouse gases are produced at the power generation source.

Concentrated solar power (CSP) generation using solar receivers is knownin the art. Briefly, concentrated solar power systems use lenses,mirrors, or other elements to focus sunlight incident on a relativelylarge area onto a small area called a solar receiver. The concentratedsunlight can be used to heat a fluid within the solar receiver. Thefluid heated within the solar receiver can be used to create energy,such as by driving a turbine to generate power or by providing asecondary heat source.

Conventional receivers for concentrating solar power consist of panelsof tubes that are arranged in a cylindrical or cubical shape to face theincoming solar irradiance. However, these configurations also maximizeradiative and convective heat losses to the environment; most of thesunlight reflected off of these surfaces is lost to the environment.

The need therefore remains for an efficient solar receiver that enableshigher efficiency power cycles.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a solar receiver according to an exemplaryembodiment of the disclosure.

FIG. 2 is an illustration of a solar receiver panel according to anexemplary embodiment of the disclosure.

FIG. 3 is an illustration of a solar receiver panel according to anotherexemplary embodiment of the disclosure.

FIG. 4 is an illustration of a solar receiver according to anotherexemplary embodiment of the disclosure.

FIG. 5 is an illustration of a solar receiver according to anotherexemplary embodiment of the disclosure.

FIG. 6 is an illustration of a solar receiver panel system according toan exemplary embodiment of the disclosure.

FIG. 7 is a partial cut away overhead view of one of the solar receiverpanel system of the solar receiver shown in FIG. 5 having the topheaders cut away to show the tubes.

FIG. 8 is an illustration of a solar receiver according to anotherexemplary embodiment of the disclosure.

SUMMARY OF THE DISCLOSURE

In an embodiment of the disclosure, a solar receiver is disclosed thatincludes a plurality of solar receiver panels disposed radially about acentral hub having a vertical axis. The plurality of solar receiverpanels includes a first fluid header, a second fluid header, and aplurality of tubes fluidly connecting the first and second fluidheaders.

In another embodiment of the disclosure, a solar receiver is disclosedthat includes a plurality of solar receiver panel systems disposedradially about a central hub having a vertical axis. The plurality ofreceiver panel systems includes a first solar receiver panel, and asecond solar receiver panel configured with the first solar receiverpanel to form a wedge shape having an apex directed away from thevertical axis.

In another embodiment of the disclosure, a solar receiver is disclosedthat includes a support panel, and a plurality of solar receiver panelsattached to and extending from the support panel. The at least one solarreceiver panel of the plurality of solar receiver panels includes afirst fluid header, a second fluid header, and a plurality of tubesfluidly connecting the first and second fluid headers.

In another embodiment of the disclosure, a solar receiver is disclosedthat includes a shroud disposed above a plurality of solar receiverpanels. The shroud is configured to retain heat by capturing heated airand reflecting radiation lost by the plurality of solar receiver panels.

One advantage of the present disclosure is to provide a solar receiverthat will significantly increase the absorbed solar radiation whilereducing heat losses (radiative and convective), yielding higher thermalefficiencies, improved performance, and reduced costs for concentratingsolar power tower systems.

Another advantage of the present disclosure is that the receiverfootprint (optical intercept area) can be smaller with the same exposedsurface area and surface irradiance, which will reduce heat losses.Large structural cavities, which are used to reduce radiative heatlosses, can also be avoided.

Other features and advantages of the present disclosure will be apparentfrom the following more detailed description of the preferredembodiment, taken in conjunction with the accompanying drawings whichillustrate, by way of example, the principles of the disclosure.

DETAILED DESCRIPTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete and will fully conveythe scope of the invention to those skilled in the art.

The present disclosure is directed to a solar receiver, hereinafterreferred to as a “receiver,” that reduces the amount of radiative energyloss while increasing absorbed radiation, yielding higher thermalefficiencies, improved performance, and reduced costs for concentratingsolar power tower systems. The disclosed receiver includes panels oftubes arranged either radially (in a star pattern) or along a verticalor horizontal plane. The disclosed receiver reduces the local radiativeview factors and heat losses and increases the amount of absorbed energyfrom the heliostat field.

The disclosed receiver can operate at high temperatures (>650° C.) whilereducing radiative and convective heat losses at high concentrationratios (˜1000 suns or more) to achieve high annual thermal efficiencies.In an embodiment, a STAR (Solar Thermal Advanced Receiver) receiver isdisclosed that reduces total heat transfer losses (radiation andconvection) of up to 50% with an increase in thermal efficiency ofnearly 10%. This translates into significant cost savings by requiringfewer heliostats for the same amount of thermal output. Achieving thesemetrics is necessary to reduce the levelized cost of electricity ofconcentrating solar power towers to levels comparable with currentfossil-fueled power plants.

FIG. 1 illustrates an embodiment of the present disclosure. According tothis embodiment, a receiver 10 is disclosed that includes a plurality ofreceiver panels 12 radially disposed about and extending from a centralhub 14. The receiver panels 12 may be referred to as blades. In thisexemplary embodiment, the receiver panels 12 radiate perpendicular fromthe central axis Y of the hub 14. The hub 14 is connected to a tower 16for elevating the receiver 10 above a surface (not shown). The receiverpanels 12 have a leading edge 17 that is distant from the hub 14, and atrailing edge 18 that is proximate to the hub 14. In this and in otherdrawings of the disclosure, the hub and other components are notnecessarily to scale, and may be large enough to contain piping andother features within. Each segment of the radial structure can bemodular, consisting of the outward radial receiver panels and theportion of the hub that connects the radial receiver panels.

Additionally, the receiver panels 12 have a first side 19 and a secondside 20 opposite the first side 19. The first and second sides 19, 20may be coated or treated with heat absorbing surfaces, coatings ortextures to efficiently capture the incident concentrated solarradiation. As can be seen in FIG. 1, both first and second sides 19, 20sides of the receiver panels 12 can be illuminated. The radiallyextending blade design increases the effective solar absorptance andefficiency by providing a light trap for the incident solar radiationwhile reducing heat losses from radiation and convection.

In this exemplary embodiment, the receiver 10 includes eight receiverpanels 12, however, in another embodiment, the receiver 10 may include 2or more receiver panels 12. In another embodiment, the receiver 10 mayinclude between 2 and 1000 receiver panels. In another embodiment, thereceiver 10 may include between 3 and 20 receiver panels. In anotherembodiment, the receiver 10 may include between 4 and 10 receiverpanels. In an embodiment, receiver panels may include one or more tubeswith or without a header. As can be seen in FIG. 1, both sides of thereceiver panels 12 can be illuminated.

The hub 14 provides a central attachment point for the receiver panels12. In addition, the hub 14 and/or tower 16 may include piping forfluidly connecting the receiver panels 12 to a fluid source and fluidreceiver (not shown) as would be appreciated by one of ordinary skill inthe art. Further in addition, the hub 14 and/or tower 16 may includepumps, valves and/or other fluid transport and control devices forproviding and/or controlling fluid to the receiver panels 12.

In this exemplary embodiment, the receiver panels 12 are attached to thehub 14. In another embodiment, the receiver panels 12 may be pivotallyattached to the hub 14 in a manner that allows the receiver panels 12 tobe pivoted about the Y axis. For example, one or more of the receiverpanels 12 may be pivoted so as to face a surface more perpendicular tosolar irradiance.

FIG. 2 illustrates an example of a receiver panel 12 according to anembodiment of the invention. As can be seen in FIG. 2, the receiverpanel 12 includes a first manifold 22, a second manifold 24, and aplurality of tubes 26 disposed between the first and second manifolds22, 24. In this exemplary embodiment, the first manifold 22 receives afluid from the hub 14 or tower 16 in the direction shown by arrow A. Thefluid is then distributed to the plurality of tubes 26 and flows indirection A′ to the second manifold 24, where it is collected and flowsto the hub 14 or tower 16 in direction A″. In another embodiment, thedirection of flow may be reversed. The first and second manifolds 22, 24may include piping, baffling or other fluid control and distributioncomponents to provide and control the flow of fluid to the tubes 26. Inthis exemplary embodiment, the tubes 26 have a generally circular crosssection. In another embodiment, the tubes 26 may have other crosssections, such as, but not limited to square, rectangular, and oval.Additionally, in this exemplary embodiment, the tubes 26 are in closeproximity or touching adjacent tubes. In an embodiment, some minimalspacing may be present to allow for expansion.

As can be seen in FIGS. 1 and 2, receiver panels 12 have first side andsecond sides 19, 20. The first and second sides 19, 20 may be coated ortreated with heat absorbing surfaces, coatings or textures toefficiently capture the incident concentrated solar radiation.

FIG. 3 illustrates another example of a receiver panel 32 according toanother embodiment of the disclosure. As can be seen in FIG. 3, thereceiver panel 32 includes receiver sub-panels 34. Similar to receiverpanel 12 shown in FIG. 2, receiver panel 32 includes a leading edge 17,a trailing edge 18, a first side 19, and a second side 20 (opposite thefirst side 19, but not shown). In this exemplary embodiment, thereceiver panel 32 includes three receiver sub-panels 34. In anotherembodiment, the receiver panel 32 may include two or more receiversub-panels. Fluid flow is indicated by arrows B. In another embodiment,the direction of fluid flow may be reversed. In another embodiment, thefluid may enter the first bottom sub-panel and be redirected to thetubes (as would be the case if the receiver panel were flipped so thebottom header was the top header. In another embodiment, the fluiddirection of the flipped receiver panel may be reversed. In thisexemplary embodiment, fluid is first provided to the tubes of the panelclosest to the leading edge 17. In another embodiment, fluid may befirst provided to the tubes of the panel closest to the trailing edge18.

Each receiver sub-panel 34 includes a first manifold 36, a secondmanifold 38, and a plurality of tubes 40 receiving fluid flow the firstmanifold 36 and providing fluid to the second manifold 38. The first andsecond manifolds 36, 38 may include piping, baffling or other fluidcontrol and distribution components to provide and control the flow offluid to the tubes 40. In this exemplary embodiment, the tubes 40 have agenerally circular cross section. In another embodiment, the tubes 40may have other cross sections, such as, but not limited to square,rectangular, and oval.

FIG. 4 illustrates another example of a receiver 50 according to anotherembodiment of the disclosure. As can be seen in FIG. 4, the receiver 50includes a plurality of receiver panels 52 and a tower 54. The receiver50 further includes a hub (not shown). In general, the receiver 50 hasthe same panel structure as the embodiment shown in FIG. 1. In addition,the receiver 50 of this embodiment includes a top shroud 56 and bottomsupports 58. The bottom supports 58 connect and stabilize the receiverpanels to the tower 54.

The top shroud 56 provides a structure that reduces both convective andradiative losses. Solar reflections and radiative thermal emissions fromthe surface of the receiver can be intercepted by the shroud andreradiated back to the receiver. In addition, the shroud impedes theupward natural convection of hot air from the receiver surface, therebyreducing convective heat losses. The top shroud 56 includes an outsidesurface 60 and an inside surface 62. The inside surface 60 may be coatedwith a durable reflective surface, and the outer surface may beinsulated to reduce convective and radiative losses.

FIGS. 5, 6 and 7 illustrate another exemplary embodiment of a receiver66 according to an embodiment of the disclosure. As can be seen in FIG.5, the receiver 66 includes a plurality of receiver panel systems 68connected to and radially disposed about a central hub 70. The pluralityof receiver panel systems 68 extend from the central hub 70 in a radialdirection. In this exemplary embodiment, the radial axis of the receiverpanel systems 68 radiate perpendicular from the central axis Y of thehub 70 in radial direction R. The hub 70 is connected to a tower 72 forelevating the receiver 66 above a surface (not shown). The receiverpanel systems 68 have a leading edge 74 that is distant from the hub 70,and a trailing edge 76 that is proximate to the hub 70.

As can be seen in FIGS. 6 and 7, the receiver panel system 68 include afirst receiver panel 78 and a second receiver panel 80 that generallycome together to form a wedge or triangular shape that apexes in theradial direction. The receiver panel system 68 may include a nose panel,cap or other structural member 82 that provides structural support andaerodynamic streamlining to the receiver panel system 68. The receiverpanel system 68 may further include a rear panel, cap or structuralmember 84 that provides structural support and connection to the hub 70.The receiver panel system 68 includes a first side 86 and a second side88. In addition, the receiver panel system 68 may include insulationand/or reflective material or components 90 (see FIG. 7, not shown onFIG. 6 for clarity) disposed behind the first and/or second receiverpanels 78, 80 for providing thermal control and/or for reflectingirradiance back upon the sub-panels. The receiver panel system 68 mayinclude additional structures and supports for joining and/or supportingthe panel components.

In this exemplary embodiment, the receiver 66 includes four receiverpanel systems 68, however, in another embodiment, the receiver 66 mayinclude 2 or more receiver panel systems 68. In another embodiment, thereceiver 66 may include between 2 and 1000 receiver panel systems. Inanother embodiment, the receiver 66 may include between 3 and 20receiver panel systems. In another embodiment, the receiver 66 mayinclude between 4 and 10 receiver panel systems. In an embodiment,receiver panels forming the receiver panel systems may include one ormore tubes with or without a header. As can be seen in FIG. 5, bothsides of the receiver 66 can be illuminated.

The hub 70 provides a central attachment point for the receiver panelsystems 68. In addition, the hub 70 and/or tower 72 may include pipingfor fluidly connecting the receiver panel systems 68 to a fluid sourceand fluid receiver (not shown) as would be appreciated by one ofordinary skill in the art. Further in addition, the hub 70 and/or tower72 may include pumps, valves and/or other fluid transport and controldevices for providing and/or controlling fluid to the receiver panelsystems 68.

In this exemplary embodiment, the receiver panel systems 68 are attachedto the hub 70. In another embodiment, the receiver panel systems 68 maybe pivotally attached to the hub 70 in a manner that allows the receiverpanel systems 68 to be pivoted about the Y axis. For example, one ormore of the 68 may be pivoted so as to face a surface more perpendicularto solar irradiance.

FIGS. 6 and 7 show a more detailed illustration of a receiver panelsystem 68 according to an embodiment of the invention. The rear cap 80has been removed from FIG. 6 for clarity. As can be seen in FIGS. 6 and7, the first and second receiver panels 78, 80 are similar in shape andstructure, and will described by referencing the first receiver panel78, while being understood that corresponding similar components areshown on the second receiver panel 80.

Referring again to FIGS. 6 and 7, the first receiver 78, which has ageneral panel structure, is structured similar to the receiver panel 32shown on FIG. 3, and includes the variations as discussed with thevarious embodiments, including, but not limited to being constructed ofa single panel. In addition, this embodiment may include piping and/orother structures that may allow for fluid to be provided between thefirst and second receiver panels 78, 80. It should be noted that in thisembodiment, illumination does not directly impact the interior side ofthe tubes of the sub-panels, although sunlight may be reflected to theinterior side of the tubes.

FIG. 8 illustrates another example of a receiver 92 according to anotherembodiment of the disclosure. As can be seen in FIG. 8, the receiver 92includes a support panel 94 and plurality of receiver panels 96. Thesupport panel 94 serves a similar function as the hub 14 (FIG. 1) of aprevious embodiment, and may include piping, pumps, and fluid andsupport structures. The plurality of receiver panels 96 extend from theplane of the receiver 92. In an embodiment, the support panel 94 may beattached to a tower as also shown in FIG. 1. The extending blade designincreases the effective solar absorptance and efficiency by providing alight trap for the incident solar radiation while reducing heat lossesfrom radiation and convection.

The receiver panels 96, which have a general panel structure, arestructured similar to the receiver panel 32 shown on FIG. 3, andincludes the variations as discussed above with the various disclosedpanel embodiments, including, but not limited to being constructed of asingle panel or multiple panels. In this exemplary embodiment, thesupport panels 96 are aligned and attached horizontally to the supportpanel 94, or in other words, the flow in the tubes is horizontal inrelation to any surface the receiver 92 is disposed above, and assimilarly shown in FIG. 3. In another embodiment, the receiver panels 96may be aligned and attached vertically upon the support panel 94. Inanother embodiment, the receiver panels 96 may be attached at any angleto the support panel 92. In this exemplary embodiment, the receiverpanels 96 are rigidly attached to the support panel 94. In anotherembodiment, the receiver panels 96 may be pivotally attached to thesupport panel 94.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the appended claims. It is intendedthat the scope of the invention be defined by the claims appendedhereto. The entire disclosures of all references, applications, patentsand publications cited above are hereby incorporated by reference.

In addition, many modifications may be made to adapt a particularsituation or material to the teachings of the disclosure withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the disclosure not be limited to the particular embodimentdisclosed as the best mode contemplated for carrying out thisdisclosure, but that the disclosure will include all embodiments fallingwithin the scope of the appended claims.

What is claimed is:
 1. A solar receiver, comprising: a flat supportpanel having a vertical and a horizontal axis; and a plurality of solarreceiver panels having planes parallel to a surface of the plurality ofsolar panels for receiving impinging solar radiation and attached to andextending from the flat, support panel; wherein at least one solarreceiver panel of the plurality of solar receiver panels comprises: afirst fluid header; a second fluid header; and a plurality of tubesfluidly connecting the first and second fluid headers; and wherein theplurality of solar receiver panels comprise a leading edge and atrailing edge, the trailing edge proximate to the flat, support paneland the leading edge opposite thereof and facing impinging solarradiation, the planes of the plurality of solar panels passing throughthe leading edges and trailing edges; and wherein the plurality of solarreceiver panels are stacked vertically over one another.
 2. The solarreceiver of claim 1, wherein the planes of the plurality of solarreceiver panels are parallel to the vertical axis of the flat supportpanel.
 3. The solar receiver of claim 1, wherein the planes of theplurality of solar receiver panels are parallel to the horizontal axisof the flat support panel.
 4. The solar receiver of claim 1, wherein atleast one solar receiver panel of the plurality of solar receiver panelsis attached to the flat, support panel to allow the plurality of solarpanels to pivot with respect to the flat support panel.
 5. The solarreceiver of claim 1, wherein at least one of the plurality of solarreceiver panels extend horizontally or perpendicular from or to thevertical axis.
 6. The solar receiver of claim 5, wherein the at least ofthe one or more of the plurality of solar receiver panels can pivot withrespect to the horizontal axis.
 7. The solar receiver of claim 1,wherein at least one of the plurality of solar receiver panels extendsvertically or parallel from or to the vertical axis.
 8. The solarreceiver of claim 7, wherein the at least one of the one or more of theplurality of solar receiver panels can pivot vertically with respect tothe vertical axis.
 9. The solar receiver of claim 1, wherein at leastone of the plurality of solar panel receivers comprises two or moresolar receiver sub-panels.
 10. The solar receiver of claim 9, whereinthe solar receiver sub-panels comprise: a first sub-panel fluid header;a second sub-panel fluid header; and a plurality of sub-panel tubesfluidly connecting the first and second sub-panel fluid headers.